Gartner has its figures for PC sales. Worldwide, Asus and Lenovo seeing lots of growth, Dell and HP losing lots of sales, Apple doesn't register in the top 5. Overall, the market remained flat. If you take a narrow view of the world and only focus on the US, things look different. In the US, everybody loses, and only Apple sees minor growth. All this excludes tablet sales, but considering people are hammering on and on and on about how it's a post-PC device, I think it makes sense to exclude it. You can't have your cake, and eat it too. Then again, who cares.

And actually, the OEMs still haven't gotten themselves out of the MHz-war mindset. They are still overbuying on CPUs and underbuying on other components. (I suppose that's why Intel is still making boatloads of money.)

Maybe things will come around. Because, it wasn't always like that - consider how Atari 2600 and NES had essentially the same CPU - launched in mid-70s, still in some then-new machines in mid-80s. Similar with Motorola 68k - launch at the turn of 70s/80s, still found in some newly introduced machines in early 90s. Clocks not much different.
PCs also had such period: while 386 was launched in 1985, XT and AT-class machines remained fairly standard for a long time - and AMD 386 (after it was finally cleared by courts...) was still able to be a big success in early 90s.

It was more about support & gfx chips ("GPU"), amount of memory... So just like now, more or less, except without any usage scenario in sight which would significantly bump the need for CPU power, like ~multimedia did in the 90s (that, and the success of "Intel Inside" & bunny suits men campaigns).